期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1999
卷号：96
期号：18
页码：10164-10169
DOI：10.1073/pnas.96.18.10164
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Interaction of syntaxin 1 with the 1D subunit of the voltage-gated L type Ca2+ channel was investigated in the pancreatic {beta} cell. Coexpression of the enhanced green fluorescent protein-linked 1D subunit with the enhanced blue fluorescent protein-linked syntaxin 1 and Western blot analysis together with subcellular fractionation demonstrated that the 1D subunit and syntaxin 1 were colocalized in the plasma membrane. Furthermore, the 1D subunit was coimmunoprecipitated efficiently by a polyclonal antibody against syntaxin 1. Syntaxin 1 also played a central role in the modulation of L type Ca2+ channel activity because there was a faster Ca2+ current run-down in cells incubated with antisyntaxin 1 compared with controls. In parallel, antisyntaxin 1 markedly reduced insulin release in both intact and permeabilized cells, subsequent to depolarization with K+ or exposure to high Ca2+. Exchanging Ca2+ for Ba2+ abolished the effect of antisyntaxin 1 on both Ca2+ channel activity and insulin exocytosis. Moreover, antisyntaxin 1 had no significant effects on Ca2+-independent insulin release trigged by hypertonic stimulation. This suggests that there is a structure-function relationship between the 1D subunit of the L type Ca2+ channel and the exocytotic machinery in the pancreatic {beta} cell.
